What happened

A new boiler was installed as part of an extension. Six months later, on remortgage, the lender asked for the Gas Safe certificate. The installer was not on the Gas Safe register.

How it was discovered

Public register search. The 'engineer' had let registration lapse two years earlier.

The consequences

Boiler removed, re-installed by a registered engineer, new certificate issued. Cost: most of the original installation again.

What homeowners can learn

Check the registration before, not after. The public registers are free and take a minute.